There exist today many types of hand-held electronic devices, each of which utilizes some sort of user interface. The user interface can include an output device in the form of a display, such as a Liquid Crystal Display (LCD), and one or more input devices, which can be mechanically actuated (e.g., switches, buttons, keys, dials, joysticks, joy pads) or electrically activated (e.g., touch pads or touch screens). The display can be configured to present visual information such as text, multi-media data, and graphics, and the input devices can be configured to perform operations such as issuing commands, making selections, or moving a cursor or selector in the electronic device.
Recently work has been progressing on integrating various devices into a single handheld device. This has further led to attempts to integrate many user interface models and devices into a single unit. A touch screen can be used in such systems for both practical and aesthetic reasons. Additionally, multi-touch capable touch screens can provide a variety of advantages for such a device.
Heretofore, it has been assumed that touch screens, whether single touch or multi-touch, could be produced by fabricating a traditional LCD screen, and disposing a substantially transparent touch sensing device in front of this screen. However, this presents a number of disadvantages, including substantial manufacturing costs.